Novel fluoroalkyl chlorosulfates and a method for their preparation

ABSTRACT

Hydrogen containing fluoroalkyl chlorosulfates of the formula:

United States Patent Young et a1.

[54] NOVEL FLUOROALKYL CHLOROSULFATES AND A METHOD FOR THEIR PREPARATION [72] Inventors: David Edward Young, Denville; Lowell Ray Anderson, Parsippany; William Burke Fox, Morristown, all of N .J

Allied Chemical Corporation, New York, N.Y.

The portion of the term of this patent subsequent to Feb. 16, 1988, has been disclaimed.

[22] Filed: Aug. 11, 1969 [21] Appl. No.: 856,240

[73] Assignee:

[ Notice:

[52] U.S. Cl ..260/456 R, 252/65, 252/67,

252/77, 260/458 [51] Int. Cl ..C07c 143/68 [58] Field of Search ..260/456 R [5 6] References Cited UNITED STATES PATENTS 1/1962 Cohen....' ..260/458 4/1966 Hauptschein ..260/456R OTHER PUBLICATIONS W. V. Cohen, Nucleophilic Substitution in Fluoroalkyl Sulfates, Sulfonates, and Related Compounds, J. Org. Chem. Vol. 26, 4021- 4026 (1961).

[151 3,681,423 45 *Aug. 1, 1972 Primary Examiner- Leon Zitver Assistant Examiner- L. B. DeCrescente Attorney-Arthur J. Plantamusa 57] ABSTRACT Hydrogen containing fluoroalkyl chlorosulfates of the formula:

R C OS 0 C 1 wherein R is selected from the group consisting of hydrogen, alkyl, fluoroalkyl and aryl with the proviso that at. least one R substituent is fluoroalkyl, and at least one carbon-hydrogen bond is present in the molecule. The alkyl and fluoroalkyl moieties may have the same or a different number of carbon atoms and each may contain up to six carbons (lower alkyl) in a These novel hydrogen containing fluorinated chlorosulfates may be prepared by reacting the corresponding hypochlorite having the formula:

R COC 1 wherein R is defined as above, with sulfur dioxide at a temperature of between about 25 to 75 C. This method ma al 0 be used to re are tertiar erfluorinated lkyi chlorosulfates hav ing no hydi ogento-carbon bonds in the molecule.

6 Claims, No Drawings CROSS REFERENCE TO RELATED APPLICATIONS Co-pending application of D. E. Young et al., entitled Process for the Preparation of Polyhaloalkyl chlorosulfates, Ser. No. 780,261, filed Nov. 29, i968, co-pending application of D. E. Gould et al., entitled Novel Hydrogen-Containing Fluoroalkyl Hypochlorites and the Process for the Preparation Thereof, Ser. No. 830,864, filed June 5, 1969.

BACKGROUND OF THE INVENTION Halogenated alkyl chlorosulfates are a known class of compounds having been disclosed in US. Pat. Nos. 3,238,240; 3,238,241; 3,248,419; 3,254,107 and 3,255,229. The fluoroalkyl chlorosulfates of this invention are characterized in that they contain at least one carbon-hydrogen bond and do not contain an ahalogenated carbon atom, i.e., one which is adjacent to the chlorosulfate group (OSO CI). The hydrogen containing fluorinated chlorosulfates of this invention are made by reacting the corresponding hydrochlorite with sulfur dioxide at about 25to 75C.

The method of this invention is distinguished from the method disclosed in co-pending application, Ser. No. 780,261, in that the reaction may be conducted at reaction temperatures of above C. At temperatures above 0C., hypochlorites having a halogen substituent on the carbon atom adjacent to the chlorosulfate group, as described in the above co-pending application, Ser. No. 780,261, react to produce large amounts of undesirable by-product such as SO FC1 and yield little or no chlorosulfate.

SUMMARY OF THE INVENTION We have discovered compounds belonging to the general class of hydrogen-containing-fiuorinated chlorosulfates having the formula:

wherein each R is selected from the group consisting of hydrogen, alkyl, fluoroalkyl and aryl with the proviso that at least one R substituent is fluoroalkyl, and at least one carbon-hydrogen bond is present in the molecule. The alkyl and fluoroalkyl moieties may contain the same or a different number of carbon atoms and each may contain up to six carbons (lower alkyl), in a straight or branched chain structure and when R contains six carbon atoms, it may represent cyclic alkyl. The aryl group may be phenyl, benzyl or tolyl. Thus, R may be The compounds of this invention are prepared by reacting the corresponding hypochlorite R COCI, wherein R is as defined above, with sulfur dioxide at 25 to 75C., to yield the novel hydrogen-containing fluorinated chlorosulfates. The reaction may be represented as follows:

(CF CI-IOCI S0 (CF CHOSO Cl The method used for the preparation of these new compounds, by reacting sulfur dioxide at about room temperature with the corresponding hypochlorite, affords substantially quantitative yields. In co-pending 0 application, Ser. No. 780,261 sulfur dioxide is used to prepare analogous chlorosulfates having a fluorine on the carbon adjacent to the chlorosulfate moiety, at a sub-zero temperature of 20 C. but yields are low. With a-halogenated hypochlorites the higher the reaction temperature the lower the yield of chlorosulfates. However, the reaction of a hydrogen-containing fiuoroalkyl hypochlorite and sulfur dioxide at 25C., produces substantially quantitative yields of the chlorosulfate. At this temperature the reaction in Ser. No. 780,261 does not proceed. Moreover, this method, using higher temperatures of up to C., is generally applicable in the preparation of perfluorinated tertiary alkyl chlorosulfates which do not contain a carbonhydrogen bond and do not have an a-fluorine atom. These compounds may be represented by the following formula:

wherein each R may be the same or different perfluoroalkyl group. As fully described in copending application Ser. No. 830,864, filed June 5, 1969, the hypochlorite starting compounds are prepared by reaction of the corresponding fluoroalcohol with chlorine monofluoride in the absence of a catalyst in a suitable closed container such as a stainless steel system. The hydrogen containing fluoroalcohol starting materials are a known class of compounds and may be purchased or prepared by known methods.

The reaction may be conducted in a closed system or in a flow system, as is known in the art. The particular apparatus used is not critical to the novel reaction and is selected based upon the availability and the requirements of one skilled in the art. The apparatus, of course, must be constructed of an inert material such as stainless steel or a plastic, such as polychlorotrifluoroethylene.

The reaction takes place readily at room temperature, however temperatures between about 0 to 50C. can be used. There is no particular advantage in the use of higher or lower temperatures since the reaction readily takes place at room temperature, which is preferred. The optimum temperature for a particular reaction can be determined routinely.

Atmospheric, sub-, or super-atmospheric pressures of up to p.s.i.g. can be used successfully in the practice of this invention. The pressures developed in a system are autogenous and vary from one reaction to another and during a reaction.

An inert solvent, such as HP or CFCl can be employed. The reaction can be carried out with the reactants in either the liquid vapor or solid phase, where an appropriate inert solvent is employed.

In order to ensure completion reaction, at least the stoichiometric amount, or preferably a slight excess, of the chlorine monofluoride reactant should be em ployed, although larger excesses will not deleteriously affect the reaction. The addition of less than the stoichiometric amount of ClF will, of course, decrease the yield of product.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The new chlorosulfates of this invention contain at least one fluoroalkyl group, at least one carbonhydrogen bond and do not have a halogenated carbonadjacent to the chlorosulfate moiety. This feature is important in the chemistry of these chlorosulfates in that useful new materials, hitherto unknown may now be prepared, such as:

(CE, CHOSO Cl-1-CsF (CF Cl-IOSO CH CF +NaC1 atoms than hydrogen atoms in the molecule: although compounds having less than 50 percent fluorine atoms based on the hydrogen atoms present are also made possible by this invention.

Within the preferred class of compounds are those in which the R substituents are CP and CH or H, such as are represented in the following formulas:

Other hydrogen containing fluorinated chlorosulfates included Within the scope of this invention are:

The compounds of this invention may be prepared by condensing the corresponding hydrogen-containing fluoroalkyl hypochlorite with sulfur dioxide using conventional vacuum techniques. The hydrogen-containing fluoroalkyl hypochlorite starting materials may be prepared as described in co-pending application Ser. No. 830,864. The reactants are mixed at sub-zero temperatures of for instance l96C., and are permitted to warm to about 25 to C., preferably 25C., after which the mixture is shaken for about 20 hours, or for a time sufficient to complete the reaction. There is no particular advantage in the use of higher or lower temperatures, since the reaction readily takes place at room temperature in excellent yield, and as mentioned above, this temperature is preferred. Excess S0, is removed, along with minor impurities, by fractionation through a cold trap, leaving a liquid product representing the chlorosulfate. The temperature of the cold trap is usually set slightly below the temperature at which the desired product has significant volatility.

In order to ensure complete reaction, at least the stoichiometric amount or preferably an excess of the sulfur dioxide reactant is employed, although other ratios will not deleteriously effect the reaction.

The reaction may be conducted in a closed system such as described in the appended examples or in a flow system as known in the art. The particular apparatus is selected based upon the availability of materials and preference of one skilled in the art. The apparatus, of course, must be constructed of a material inert to, the reactants, such as stainless steel, polychlorotrifluoroethylene and the like.

The autogenous pressures developed within the system may vary from one reaction to another and during a reaction. The pressure within the system is not critical and the reaction is usually conducted under the pressure developed during the reaction as a result of the vapor pressure of S0 at the reaction temperatures.

An inert solvent may be employed such as for example HF and CFCl without departing from the spirit of this invention.

The following examples are intended to illustrate specific embodiments of this invention and are not intended to limit the scope thereof.

EXAMPLE 1. PREPARATION OF (CF Cl-IOSO Cl Conventional vacuum techniques in a Monel-nickel metal system were used to condense (CE-,hCl-IOCI (10 mmol) and S0 12 mmol) into a stainless steel cylinder equipped with a Hoke valve at l96C. The reactants were allowed to warm to 25C. and shaken mechanically for 20 hours. The reaction mixture was then fractionated through a cold trap at 45C. to remove excess S0 and minor impurities, leaving a clear, colorless liquid product. The product was identified by its infrared spectrum, its F and H nmr spectra, and by elemental analysis. The yield was substantially quantitative.

Elemental Analysis for (CF CHOSO Cl Found Calcd %C 13.30 13.51 %F 42.09 42.78 %C113.20 13.32

EXAMPLE 2. PREPARATION OF (CF3)2(CH3) coso cl (CF (CH )COCI mmol) and S0 (12 mmol were reacted as in the previous example for 24 hours at 25C. The product, was isolated by fractionation through a 45C. cold trap. The clear, colorless liquid was identified by its elemental analysis. The yield was substantially quantitative.

Elemental Analysis for (CF (CI-I )COSO Cl Found Calc'd %C 17.06 17.11 %F 40.50 40.65 %Cl 12.28 12.65

EXAMPLE 3. PREPARATION OF CF CI-I OSO Cl CFaCHgOCl (10 mmol) and S0 (12 mmol) were reacted as in the previous examples for 24 at 25C. The clear, colorless liquid product remained after removing impurities by fractionation through a 45C. cold trap. It was identified by its infrared spectrum, its F and H nmr spectra, and by elemental analysis. Again the yield was substantially quantitative.

Elemental Analysis for CF Cl-I OSO Cl Found Calc'd %C 12.15 12.08 %F 28.13 28.70 %c117.50 17.87

EXAMPLE 4. REACTION OF (CF CHOSO CL WITH CESIUM FLUORIDE (CF CHOSO Cl (2mmol) containing no halogen atom on the carbon adjacent to the chlorosulfate function was reacted with approximately 5 mmol of CsF in a glass reaction tube at 25C. for 20 hours. The reaction mixture was agitated by a magnetic stirring bar. Fractionation of the reaction mixture revealed that 80 percent of the (CF- CI-IOSO Cl had been converted to the corresponding fluorosulfate, (CF CHOSO F according to the following:

The flurosulfate product was identified by its infrared spectrum, its F and H nmr spectra, and by elemental analysis. It was found to be a thermally and oxidatively stable liquid. Other than unconverted chlorosulfate, no other volatile materials were present at the termination of the reaction.

EXAMPLE 5. REACTION OF (CF CFOSO CL WITH CESIUM FLUORIDE The reaction of (CF CFOSO CI (2mmol), containing an a-fluorine atom on the carbon adjacent to the chlorosulfate function, was attempted with approximately 5 mmol of CsF in a glass reaction tube at C. with stirring. After 2 hours the volatile materials of the reaction were fractionated through cold traps of 80 EXAMPLE 6. REACT ION OF CF CI-I OSO CI with NaOCH CF The CR Cl-I OSO Cl (5 mmol) was reacted with NaOCI-I CF (5 mmol) in diethylether at 25C. in a glass reaction vessel. A white precipitate was formed due to NaCl formation. After 6 hours the reaction mixture was fractionated through a 23C. cold trap. The product was retained as a clear, colorless liquid. It was identified as being a stable ester having the formula:

We claim: 1. The process for chlorosulfate of the formula:

wherein each R substituent is selected from the group consisting of hydrogen, lower alkyl, and lower fluoroalkyl, with the proviso that at least one R substituent is fluoroalkyl and at least one carbon-hydrogen bond is present in the molecule, comprising the steps of reacting a hypochlorite of the formula:

R COCI wherein said R is as defined above, with sulfur dioxide, at a reaction temperature of between about -25C. and C., for a time sufficient to produce said chlorosulfate.

2. The process according to claim 10, wherein said reaction temperature is about 25C.

3. The process according to claim 2 wherein the hypochlorite is:

preparing a fluoroalkyl (CFQ CHOCI.

4. The process according to claim 2 wherein the hypochlorite is:

(CF (CH )COCI.

5. The compound which is (CF CI-IOSO Cl.

6. The compound which is 

2. The process according to claim 10, wherein said reaction temperature is about 25* C.
 3. The process according to claim 2 wherein the hypochlorite is: (CF3)2CHOCl.
 4. The process according to claim 2 wherein the hypochlorite is: (CF3)2(CH3)COCl.
 5. The compound which is (CF3)2CHOSO2Cl.
 6. The compound which is (CF3)2(CH3)COSO2Cl. 